For years, the problem of preventing unauthorized access to a garage having an overhead door equipped with an automatic door opening and closing system has been of concern to the general populace. A wide variety of attempts have been made to, in some manner, disable such an automatic garage door opening mechanism in order to prevent unauthorized access. Representative of these attempts are those generally exemplified by the teachings of U.S. Pat. Nos. 2,530,629; 2,607,586; 4,254,582; 4,771,218 and 4,819,379. It has also been common to provide various key-locking devices for securing a door in its closed position; however, these devices have usually required the manual turning of a key and the consequent inconvenience involved with it. None of the foregoing attempts has been fully satisfactory for sectional garage doors, and as a result, more effective, more convenient arrangements have continued to be sought.